Bigger Injectors
 

I seem to remember there being problems with running low impedance injectors with MS in our configuration. Is that still the case? If so how do I get around it so I can fit bigger injectors? I plan on going FI pretty soon, and I seriously doubt by stock ones will cope considering I hit 75%DC as a stock car...

Thanks!

Search for some posts by AlHounos I think he is running DSM 440 injectors.

Yeah, but I'm using resistors. I had trouble with tach signal using the MS PWM.

They're 450s, which seems like just big enough for the limits of the stock 1.6.
I'm at 80% DC at 11.5:1 at 7000rpm at 180kpa.

sounds good to me! which DSM injectors did you use? (I'm in the UK so it may a be more difficult tracing them?)

Can you describe whats involved with adding resistors to the injectors? is is just a case of addin one in-line with the signal line. I assume this converts them to High Impedance and the Impedance settings in MS don't need adjusting?

Thanks!

They're from a first gen turbo eclipse. They are blue.
I actually used a resistor pack that I got with the injectors that comes stock on the eclipse. But you can just wire separate resistors inline with the power wires.
Yes, just set them up in MT as high impedance.

lots of larger injectors available for PnP. see my FAQ.

i bought some high impedence 550cc injectors off of kungfu jesus on this forum. Should be arriving monday, ill post how it goes.

hrm, looks like I need a set of early RX7 injectors for plug and play high impedance then!

great FAQ thanks!

Watch out which ones you get from the 1st Gen DSM's. Automatics have smaller 330cc injectors.

Thanks for the heads up.

There's little pickings on UK ebay, but there's a lot on US ebay, this is donna sound dumb, however, are all injectors the same fitment into the rail? I'd assume not, but how do you tell if they will fit?

I've searched for DSM injectors and there's quite a few 450cc ones, from Mitsubishi Talons, and Eclipse's. Would they fit? Are honda Injectors a similar fitment?

Thanks!

The ones in the FAQ will fit.

I got a set of Supra 305ccs and they were AU$72 delivered to Australia from the US. :eek5: $72 is only a couple of quid! :bigtu: :gtfo:

HTH

for the sizes I need the FAQ's slim pickings ;) I need 420's minimum, 305 is way too small!

I'm just hoping all DSM injectors will fit.

They will fit, they are just a little shorter than the stockers. The best injectors for a miata is the rx7 550s, truly PNP and the perfect size. DSM are easier to find and probably cheaper though, and only too small if you plan on building the engine.

I've got an M62 on the way so I doubt I'll need much higher.

Many thanks for the info Al!

(there's a set of RX7 injectors on the bay now.... hrm!!

question about the resistor packs: Since MS is batch fire, do you need 1 resistor for each injector, or can you use 1 resistor for each bank?

I know there are PnP high ohm injectors that work. But it seems it's easier to find the low ohm injectors (more abundant), and Honda resistor packs are about $10 or so on ebay, so that seems like an inexpensive/easier way to go.

Buy the resistor pack. It will be easy to see how to wire it up once you get it. it basically is a 1 into 4 adapter, with resistors.

So I gather from what you are saying is the resistors are wired on the 12v side? so is would be: 12v+ -> resistor pack -> injectors -> MS ?

yup.